/* ═══════════════════════════════════════════════════════════════════════════
   PHYSICSFORUM.ORG — HOMEPAGE STYLES
   Mobile-first. All colours via CSS custom properties from tokens.css.
   ═══════════════════════════════════════════════════════════════════════════ */

/* ── Section Base ── */
.hp-section {
  padding: var(--space-16) var(--space-4);
}
.hp-section-header {
  text-align: center;
  margin-bottom: var(--space-12);
}
.hp-section-header h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--text-3xl);
  color: var(--color-space-navy);
  letter-spacing: -0.02em;
  line-height: 1.15;
}
.hp-section-header .subtitle {
  font-family: var(--font-body);
  font-size: var(--text-lg);
  color: var(--color-neutron-grey);
  margin-top: var(--space-3);
  font-style: italic;
}

/* ── 3.1 HERO SECTION (lighter, no black texture) ── */
.hero {
  position: relative;
  min-height: 560px;
  height: auto;
  padding: 100px 16px 80px;
  background:
    radial-gradient(1200px 600px at 20% 20%, rgba(37,99,235,0.25), transparent 60%),
    radial-gradient(900px 500px at 80% 80%, rgba(124,58,237,0.18), transparent 60%),
    linear-gradient(135deg, #1B3A6B 0%, #2563EB 50%, #4F46E5 100%);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
.hero canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}
.hero-content {
  position: relative;
  z-index: var(--z-above);
  text-align: center;
  max-width: 900px;
  padding: 0 var(--space-6);
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: rgba(37,99,235,0.15);
  border: 1px solid rgba(37,99,235,0.3);
  border-radius: var(--radius-full);
  color: var(--color-ice-blue);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.03em;
  margin-bottom: var(--space-6);
  backdrop-filter: blur(8px);
}
.hero-badge svg {
  width: 16px;
  height: 16px;
}
.hero-headline {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: var(--text-4xl);
  line-height: 1.05;
  letter-spacing: -0.03em;
  color: #fff;
  margin-bottom: var(--space-6);
}
.hero-headline .line-1 { color: #fff; }
.hero-headline .line-2 {
  background: linear-gradient(90deg, var(--color-electric) 0%, var(--color-quantum-gold) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-headline .line-3 { color: #fff; }
.hero-lead {
  font-family: var(--font-body);
  font-size: var(--text-lg);
  color: var(--color-neutron-grey);
  max-width: 600px;
  margin: 0 auto var(--space-8);
  line-height: 1.6;
}
.hero-ctas {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
  margin-bottom: var(--space-10);
}
.hero-ctas .btn {
  font-size: var(--text-base);
  padding: var(--space-4) var(--space-8);
}
.hero-ctas .btn-gold {
  font-weight: 700;
  box-shadow: 0 0 30px rgba(245,158,11,0.35);
}
.hero-ctas .btn-secondary {
  border-color: rgba(255,255,255,0.3);
  color: #fff;
}
.hero-ctas .btn-secondary:hover {
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.5);
}

/* Hero Stats */
.hero-stats {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-6);
}
.hero-stat {
  text-align: center;
}
.hero-stat .number {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--text-2xl);
  color: var(--color-quantum-gold);
  line-height: 1;
}
.hero-stat .label {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  margin-top: var(--space-1);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.hero-stat-divider {
  width: 1px;
  background: rgba(148,163,184,0.3);
  display: none;
}

/* Scroll indicator */
.scroll-indicator {
  position: absolute;
  bottom: var(--space-8);
  left: 50%;
  transform: translateX(-50%);
  z-index: var(--z-above);
  cursor: pointer;
  animation: bounceDown 2s ease-in-out infinite;
}
.scroll-indicator svg {
  width: 32px;
  height: 32px;
  color: var(--color-neutron-grey);
  transition: color 0.3s;
}
.scroll-indicator:hover svg {
  color: var(--color-quantum-gold);
}
@keyframes bounceDown {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(10px); }
}

/* ── 3.2 LIVE ACTIVITY STRIP ── */
.activity-strip {
  background: var(--color-academic-blue);
  padding: var(--space-3) 0;
  overflow: hidden;
  position: relative;
}
.activity-strip-inner {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  white-space: nowrap;
}
.activity-label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  background: rgba(16,185,129,0.2);
  border: 1px solid rgba(16,185,129,0.3);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-fusion-green);
  flex-shrink: 0;
  margin: 0 var(--space-4);
}
.activity-item {
  font-size: var(--text-sm);
  color: var(--color-ice-blue);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.activity-dot {
  width: 6px;
  height: 6px;
  background: var(--color-fusion-green);
  border-radius: 50%;
  flex-shrink: 0;
}
.activity-time {
  color: var(--color-neutron-grey);
  margin-left: var(--space-1);
}

/* ── 3.3 FEATURED CONTENT BLOCK (FIXED — proper sizing) ── */
.featured-block {
  padding: var(--space-16) var(--space-4);
  background: #F8FAFC;
}
.featured-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
  max-width: 1280px;
  margin: 0 auto;
  align-items: stretch;
}
.featured-card {
  position: relative;
  background: #fff;
  border: 1px solid rgba(148,163,184,0.18);
  border-radius: 16px;
  padding: 24px;
  transition: box-shadow 0.2s ease, transform 0.2s ease;
  overflow: visible;
  display: flex;
  flex-direction: column;
  min-height: 420px;
  box-shadow: 0 2px 6px rgba(15,23,42,0.04);
}
.featured-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}
.featured-card.discussion {
  border-left: 4px solid var(--color-quantum-gold);
  background: linear-gradient(135deg, rgba(245,158,11,0.03) 0%, var(--color-photon-white) 30%);
}
.featured-card.article {
  border-left: 4px solid var(--color-electric);
}
.featured-card.problem {
  border-left: 4px solid var(--color-fusion-green);
}
.featured-card .card-badge {
  margin-bottom: var(--space-4);
}
.featured-card h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-xl);
  color: var(--color-space-navy);
  line-height: 1.3;
  margin-bottom: var(--space-3);
}
.featured-card h3 a {
  color: inherit;
}
.featured-card h3 a:hover {
  color: var(--color-electric);
}
.featured-card .meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
  margin: var(--space-4) 0;
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
}
.featured-card .meta .stat {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
}

/* Article card */
.featured-card .article-visual {
  height: 140px;
  background: linear-gradient(135deg, var(--color-ice-blue) 0%, var(--color-academic-blue) 100%);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-4);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.featured-card .article-visual svg {
  width: 80px;
  height: 80px;
  opacity: 0.7;
}
.featured-card .article-excerpt {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--color-dark-grey);
  line-height: 1.6;
  margin-bottom: var(--space-4);
}

/* Problem card */
.difficulty-tabs {
  display: flex;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}
.difficulty-tab {
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 600;
  cursor: pointer;
  background: rgba(148,163,184,0.1);
  color: var(--color-neutron-grey);
  transition: var(--transition-fast);
  border: none;
}
.difficulty-tab.active,
.difficulty-tab:hover {
  background: var(--color-fusion-green);
  color: #fff;
}
.countdown {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-dark-grey);
  margin-top: var(--space-4);
}
.countdown svg {
  width: 16px;
  height: 16px;
  color: var(--color-quantum-gold);
}

/* ── 3.4 TOPIC BROWSER ── */
.topic-browser {
  background: rgba(148,163,184,0.06);
  padding: var(--space-16) var(--space-4);
}
.topic-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
  max-width: 1280px;
  margin: 0 auto;
}
.topic-card {
  background: var(--color-photon-white);
  border: 1px solid rgba(148,163,184,0.12);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  text-align: center;
  cursor: pointer;
  transition: var(--transition-base);
  position: relative;
}
.topic-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg), 0 0 0 2px rgba(37,99,235,0.2);
}
.topic-card .topic-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto var(--space-3);
  color: var(--color-electric);
  transition: var(--transition-spring);
}
.topic-card:hover .topic-icon {
  transform: scale(1.15);
  color: var(--color-quantum-gold);
}
.topic-card .topic-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-sm);
  color: var(--color-space-navy);
  margin-bottom: var(--space-1);
}
.topic-card .topic-desc {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  line-height: 1.4;
  margin-bottom: var(--space-3);
}
.topic-card .topic-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-4);
  font-size: var(--text-xs);
  color: var(--color-dark-grey);
}
.topic-card .active-dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  background: var(--color-fusion-green);
  border-radius: 50%;
  margin-right: var(--space-1);
}
.topic-browser-footer {
  text-align: center;
  margin-top: var(--space-10);
}
.topic-browser-footer a {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-electric);
}

/* ── 3.5 HOW IT WORKS ── */
.how-it-works {
  background: var(--color-space-navy);
  padding: var(--space-20) var(--space-4);
  position: relative;
  overflow: hidden;
}
.how-it-works .hp-section-header h2 {
  color: #fff;
}
.how-it-works .hp-section-header .subtitle {
  color: var(--color-neutron-grey);
}
.how-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-10);
  max-width: 1000px;
  margin: 0 auto;
  position: relative;
}
.how-step {
  text-align: center;
  position: relative;
}
.how-step .step-number {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(3rem, 8vw, 5rem);
  color: var(--color-quantum-gold);
  opacity: 0.15;
  position: absolute;
  top: -20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 0;
  line-height: 1;
}
.how-step .step-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto var(--space-4);
  position: relative;
  z-index: 1;
  color: var(--color-electric);
}
.how-step h3 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--text-xl);
  color: #fff;
  margin-bottom: var(--space-2);
  position: relative;
  z-index: 1;
}
.how-step p {
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-neutron-grey);
  max-width: 300px;
  margin: 0 auto;
  line-height: 1.6;
  position: relative;
  z-index: 1;
}
.how-cta {
  text-align: center;
  margin-top: var(--space-12);
}
.how-cta .lead {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  color: var(--color-neutron-grey);
  margin-bottom: var(--space-4);
}

/* ── 3.6 PHYSICS FACT OF THE DAY ── */
.fact-of-day {
  background: var(--color-ice-blue);
  padding: var(--space-16) var(--space-4);
  text-align: center;
}
.fact-label {
  display: inline-block;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-electric);
  margin-bottom: var(--space-6);
}
.fact-equation {
  background: var(--color-photon-white);
  border-radius: var(--radius-xl);
  padding: var(--space-8) var(--space-6);
  margin: 0 auto var(--space-6);
  max-width: 700px;
  box-shadow: var(--shadow-md);
  overflow-x: auto;
  font-size: var(--text-xl);
  min-height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.fact-title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--text-2xl);
  color: var(--color-space-navy);
  margin-bottom: var(--space-3);
}
.fact-explanation {
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-dark-grey);
  max-width: 600px;
  margin: 0 auto var(--space-6);
  line-height: 1.75;
}
.fact-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
}
.fact-nav button {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-md);
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-fast);
  border: none;
}
.fact-nav .fact-prev,
.fact-nav .fact-next {
  background: var(--color-photon-white);
  color: var(--color-electric);
  border: 1.5px solid var(--color-electric);
}
.fact-nav .fact-prev:hover,
.fact-nav .fact-next:hover {
  background: var(--color-electric);
  color: #fff;
}
.fact-nav .fact-discuss {
  background: transparent;
  color: var(--color-dark-grey);
}
.fact-nav .fact-discuss:hover {
  color: var(--color-electric);
}
.fact-indicator {
  color: var(--color-neutron-grey);
  font-size: var(--text-sm);
  font-weight: 500;
}

/* ── 3.7 TESTIMONIALS ── */
.testimonials {
  background: rgba(148,163,184,0.05);
  padding: var(--space-16) var(--space-4);
}
.testimonials-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
  max-width: 1100px;
  margin: 0 auto;
}
.testimonial-card {
  background: var(--color-photon-white);
  border: 1px solid rgba(148,163,184,0.12);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: var(--transition-base);
}
.testimonial-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.testimonial-header {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}
.testimonial-avatar {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--text-lg);
  color: #fff;
  flex-shrink: 0;
}
.testimonial-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-space-navy);
}
.testimonial-role {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  margin-top: var(--space-1);
}
.testimonial-location {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  margin-left: auto;
}
.testimonial-stars {
  color: var(--color-quantum-gold);
  margin-bottom: var(--space-3);
  display: flex;
  gap: 2px;
}
.testimonial-stars svg {
  width: 16px;
  height: 16px;
}
.testimonial-quote {
  font-family: var(--font-body);
  font-style: italic;
  font-size: var(--text-sm);
  color: var(--color-dark-grey);
  line-height: 1.7;
}
.testimonial-since {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  margin-top: var(--space-3);
  font-family: var(--font-display);
}

/* ── 3.8 RECENT DISCUSSIONS FEED ── */
.recent-discussions {
  padding: var(--space-16) var(--space-4);
  background: var(--color-photon-white);
}
.recent-discussions .hp-section-header h2 {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
}
.live-dot {
  width: 10px;
  height: 10px;
  background: var(--color-fusion-green);
  border-radius: 50%;
  animation: pulseDot 2s ease-in-out infinite;
}
@keyframes pulseDot {
  0%, 100% { box-shadow: 0 0 0 0 rgba(16,185,129,0.4); }
  50% { box-shadow: 0 0 0 8px rgba(16,185,129,0); }
}

.discussions-list {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
}
.discussion-row {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-2);
  border-bottom: 1px solid rgba(148,163,184,0.12);
  transition: var(--transition-fast);
  flex-wrap: wrap;
}
.discussion-row:hover {
  background: var(--color-ice-blue);
  border-radius: var(--radius-md);
}
.discussion-row .cat-badge {
  flex-shrink: 0;
}
.discussion-row .thread-title {
  flex: 1 1 300px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-sm);
  color: var(--color-space-navy);
  line-height: 1.4;
  min-width: 0;
}
.discussion-row .thread-title a {
  color: inherit;
}
.discussion-row .thread-title a:hover {
  color: var(--color-electric);
}
.discussion-row .thread-meta {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  flex-shrink: 0;
  margin-left: auto;
}
.discussion-row .thread-meta .meta-item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
}
.discussion-footer {
  text-align: center;
  margin-top: var(--space-8);
}

/* ── 3.9 FEATURED FELLOWS ── */
.featured-fellows {
  background: var(--color-academic-blue);
  padding: var(--space-16) var(--space-4);
}
.featured-fellows .hp-section-header h2 {
  color: #fff;
}
.featured-fellows .hp-section-header .subtitle {
  color: var(--color-neutron-grey);
}
.fellows-scroll {
  display: flex;
  gap: var(--space-6);
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  padding-bottom: var(--space-4);
  max-width: 1280px;
  margin: 0 auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(255,255,255,0.15) transparent;
}
.fellows-scroll::-webkit-scrollbar { height: 6px; }
.fellows-scroll::-webkit-scrollbar-track { background: transparent; }
.fellows-scroll::-webkit-scrollbar-thumb {
  background: rgba(255,255,255,0.15);
  border-radius: var(--radius-full);
}
.fellow-card {
  flex: 0 0 240px;
  scroll-snap-align: start;
  background: var(--color-photon-white);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  text-align: center;
  transition: var(--transition-base);
}
.fellow-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}
.fellow-avatar {
  width: 72px;
  height: 72px;
  border-radius: var(--radius-full);
  margin: 0 auto var(--space-4);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: var(--text-2xl);
  color: #fff;
}
.fellow-card h4 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-space-navy);
  margin-bottom: var(--space-1);
}
.fellow-card .fellow-title {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  margin-bottom: var(--space-2);
}
.fellow-card .fellow-field {
  margin-bottom: var(--space-3);
}
.fellow-card .fellow-ama {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  margin-bottom: var(--space-4);
}

/* ── 3.10 NEWSLETTER CTA ── */
.newsletter-cta {
  position: relative;
  background: linear-gradient(135deg, var(--color-space-navy) 0%, var(--color-academic-blue) 100%);
  padding: var(--space-20) var(--space-4);
  text-align: center;
  overflow: hidden;
}
.newsletter-cta::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 20% 50%, rgba(37,99,235,0.08) 0%, transparent 50%),
    radial-gradient(circle at 80% 30%, rgba(245,158,11,0.05) 0%, transparent 40%);
  pointer-events: none;
}
.newsletter-content {
  position: relative;
  z-index: 1;
  max-width: 600px;
  margin: 0 auto;
}
.newsletter-content h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--text-3xl);
  color: #fff;
  margin-bottom: var(--space-4);
  letter-spacing: -0.02em;
}
.newsletter-content .subtext {
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-neutron-grey);
  line-height: 1.7;
  margin-bottom: var(--space-6);
}
.newsletter-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  max-width: 480px;
  margin: 0 auto var(--space-4);
}
.newsletter-form input[type="email"] {
  flex: 1;
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius-lg);
  border: 1.5px solid rgba(255,255,255,0.2);
  background: rgba(255,255,255,0.08);
  color: #fff;
  font-family: var(--font-display);
  font-size: var(--text-base);
  transition: var(--transition-fast);
}
.newsletter-form input[type="email"]::placeholder {
  color: var(--color-neutron-grey);
}
.newsletter-form input[type="email"]:focus {
  outline: none;
  border-color: var(--color-electric);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.2);
}
.newsletter-guarantee {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  line-height: 1.6;
}
.newsletter-badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-4);
  margin-top: var(--space-4);
}
.newsletter-badges span {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
}

/* ── Scroll Reveal Animations ── */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── RESPONSIVE: Tablet (640px+) ── */
@media (min-width: 640px) {
  .hero-headline { font-size: var(--text-5xl); }
  .hero-ctas { flex-direction: row; }
  .hero-stats { gap: var(--space-10); }
  .hero-stat-divider { display: block; }
  .featured-grid { grid-template-columns: 1fr 1fr; gap: var(--space-5); }
  .featured-card.problem { grid-column: span 2; }
  .topic-grid { grid-template-columns: repeat(3, 1fr); }
  .how-grid { flex-direction: row; gap: var(--space-6); }
  .how-step { flex: 1; }
  .testimonials-grid { grid-template-columns: repeat(2, 1fr); }
  .discussion-row { flex-wrap: nowrap; }
  .newsletter-form { flex-direction: row; }
}

/* ── RESPONSIVE: Desktop (1024px+) ── */
@media (min-width: 1024px) {
  .hp-section { padding: var(--space-24) var(--space-8); }
  .hero-headline { font-size: var(--text-6xl); }
  .hero-lead { font-size: var(--text-xl); }
  .featured-grid { grid-template-columns: repeat(3, minmax(0,1fr)); gap: var(--space-6); }
  .featured-card.problem { grid-column: span 1; }
  .featured-card { min-height: 460px; padding: 28px; }
  .featured-card h3 { font-size: var(--text-lg); }
  .topic-grid { grid-template-columns: repeat(5, 1fr); }
  .testimonials-grid { grid-template-columns: repeat(3, 1fr); }
  .discussions-list { padding: 0 var(--space-8); }
}

/* ── RESPONSIVE: Wide (1280px+) ── */
@media (min-width: 1280px) {
  .hp-section-header h2 { font-size: var(--text-4xl); }
  .topic-grid { max-width: 1200px; }
}

/* ═══════════════════════════════════════════════════════════════════════════
   ADDITIONAL FIXES — v3.1 (added by FIX patch)
   ═══════════════════════════════════════════════════════════════════════════ */

/* Featured card content alignment */
.featured-card h3 {
  font-size: var(--text-lg);
  line-height: 1.35;
  margin-bottom: 12px;
  flex-shrink: 0;
}
.featured-card .meta {
  flex-wrap: wrap;
  font-size: var(--text-xs);
}
.featured-card .article-excerpt,
.featured-card #problem-statement {
  flex: 1;
  font-size: var(--text-sm);
  color: #475569;
  line-height: 1.55;
}
.featured-card .btn {
  margin-top: auto;
  align-self: flex-start;
}
.featured-card .article-visual { height: 110px; }
.featured-card .article-visual svg { width: 60px; height: 60px; }
.featured-card .card-badge { margin-bottom: 12px; font-size: 11px; }
.difficulty-tabs {
  display: flex;
  gap: 6px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}
.difficulty-tab {
  font-size: 11px;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid rgba(148,163,184,0.3);
  background: #fff;
  color: #475569;
  cursor: pointer;
  font-weight: 600;
}
.difficulty-tab.active {
  background: var(--color-fusion-green);
  color: #fff;
  border-color: var(--color-fusion-green);
}

/* Hero text contrast on lighter gradient */
.hero-content { color: #fff; }
.hero-headline { color: #fff; }
.hero-lead { color: rgba(255,255,255,0.92); }
.hero-stat .number { color: var(--color-quantum-gold); }
.hero-stat .label { color: rgba(255,255,255,0.78); }

/* Topic grid: 2-cols phone, 3 cols tablet, 4 cols desktop, 5 cols wide */
.topic-grid {
  grid-template-columns: repeat(2, minmax(0,1fr));
  gap: 14px;
}
.topic-card { padding: 18px 14px; }
.topic-card .topic-name { font-size: var(--text-base); }
.topic-card .topic-desc { font-size: 12px; margin-bottom: 10px; min-height: 32px; }
.topic-card .topic-stats { font-size: 11px; color: var(--color-neutron-grey); }
@media (min-width: 640px) {
  .topic-grid { grid-template-columns: repeat(3, minmax(0,1fr)); }
}
@media (min-width: 1024px) {
  .topic-grid { grid-template-columns: repeat(5, minmax(0,1fr)); }
}